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3 years ago

What is the amount of heat absorbed when the temperature of 75 grams of water increases from 20 to 75

Chemistry

2 answers:

german3 years ago

8 0

Answer:

55°C

Explanation:

original is 20

after gaining heat is 75

75 - 20 = 55

Sindrei [870]3 years ago

7 0

Answer:

17242,5J

Explanation:

Given parameters:

Mass of water = 75g

Initial temperature = 20°C

Final temperature = 75°C

Unknown:

Amount of heat absorbed = ?

Solution

To find the amount of heat absorbed by water;

H = mcΔt

m is the mass

c is the specific heat capacity of water = 4.18J/g°C

Insert the parameters and solve;

H = 75 x 4.18 x (75 - 20)

H = 17242,5J

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Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel ro

melamori03 [73]

Answer: The mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For nickel:

Given mass of nickel = 14.8 g

Molar mass of nickel = 58.7 g/mol

Putting values in equation 1, we get:

$\text{Moles of nickel}=\frac{14.8g}{58.7g/mol}=0.252mol$

For the given chemical reaction:

$3NiO(s)+2Al(s)\rightarrow 3Ni(l)+Al_2O_3(s)$

For nickel (II) oxide:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 3 moles of nickel (II) oxide

So, 0.252 moles of nickel will be produced from $\frac{3}{3}\times 0.252=0.252mol$ of nickel (II) oxide

Now, calculating the mass of nickel (II) oxide by using equation 1:

Molar mass of nickel (II) oxide = 74.7 g/mol

Moles of nickel (II) oxide = 0.252 moles

Putting values in equation 1, we get:

$0.252mol=\frac{\text{Mass of nickel (II) oxide}}{74.7g/mol}\\\\\text{Mass of nickel (II) oxide}=(0.252mol\times 74.7g/mol)=18.8g$

For aluminium:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 2 moles of aluminium

So, 0.252 moles of nickel will be produced from $\frac{2}{3}\times 0.252=0.168mol$ of aluminium

Now, calculating the mass of aluminium by using equation 1:

Molar mass of aluminium = 27 g/mol

Moles of aluminium = 0.168 moles

Putting values in equation 1, we get:

$0.168mol=\frac{\text{Mass of aluminium}}{27g/mol}\\\\\text{Mass of aluminium}=(0.168mol\times 27g/mol)=4.54g$

Hence, the mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

4 0

3 years ago

An atom in the ground state contains 8 valence electrons this atom is classified as a

Alekssandra [29.7K]

Noble Gas. Metals have 1 or 2 Valence Electrons. Halogens have 7 Valence Electrons. Semi-Metals can have different amounts.

5 0

3 years ago

Read 2 more answers

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound a

Margarita [4]

Answer:

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound as an alcohol.

Explanation:

Alcohols belong to a group of organic compounds which contain -OH group as the functional group.

So alcohols have the same carbon -hydrogen bonds as alkanes and the -OH functional group identifies the compound as an alcohol.

8 0

3 years ago

(02.01 MC)

inna [77]

It is likely the neutral atom has 6 protons and 6 electrons; while the negatively charged atom has 7 or more electrons.

The mass of an atom, commonly known as the atomic mass is determined by the number of protons and neutrons as electrons have a very low mass.

This means two atoms can have the same number of protons and neutrons, but a different number of electrons, which would make the atom be charged negatively or positively.

Based on this, if there are two atoms, each with 6 protons but one of these is negatively charged it is because the second atom has 1 or more extra.

Neutral atom:

This atom has 6 protons and an unknown number of neutrons located in the nucleus.
This atom has 6 electrons that orbit the nucleus.
The first energetic level will include 2 electrons while the second energetic level will include the 4 remaining electrons.

Negatively-charged atom:

This atom has 6 protons and an unknown number of neutrons located in the nucleus.
This atom has 7 or even more electrons that orbit the nucleus.
The first energetic level will include 2 electrons while the second energetic level will include up to 8 electrons.

Learn more about atoms in: brainly.com/question/13981855

8 0

2 years ago

Calculate the density of nitrogen gas, in grams per liter, at stp.

lesantik [10]

Standard temperature is 273 K

Standard pressure is 1 atm

We use the ideal gas equation to find out density of nitrogen gas in g/L

Ideal gas equation:

$PV = nRT\\ PV = (\frac{Mass}{Molar mass)}RT\\ P(Molar mass) = (\frac{Mass}{Volume})RT\\ \frac{Mass}{Volume}=\frac{P(molar mass)}{RT} \\ Density = \frac{P(Molar mass)}{RT}$

Molar mass of $N_{2} = 28 g/mol$

Pressure = 1 atm

Temperature = 273 K

$Density = \frac{(1atm)(28 g/mol)}{(0.08206 \frac{L.atm}{mol.K})(273 K)}$

= 1.25 g/L

Therefore, density of nitrogen gas at STP is 1.25 g/L

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3 years ago